Process of reducing hot metal bars into sheets.



Patented July as, 1903.

FFICE'.

ATENT THOMAS V. ALLIS, OF BRIDGEPORT, CONNECTICUT.

PROCESS OF REDUCING HOT METAL BA RS INTO SHEETS.

SPECIFICATION forming part of Letters Patent No. 734,795, dated July 28, 1903.

.- Application filed February 19, 1903. Serial No. 144,147. (No specimens.)

T at whom it may concern.-

Be itknown thatI, THOMAS V. ALLIS, a citizen of the United States, residing at Bridgeport, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvementsin' Processes of Reducing Hot Metal Barsinto Sheets; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as Will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to a certain new and useful process of manufacturing thin metal sheets in piles or packs, and particularly black plate, by hot-rolling.

That my improved process may be clearly understood by those skilled in the art and in order to difierentiate it from the ordinary process heretofore employed I will first describe in a general way how sheets in piles or packs and black plate are now produced.

The term pile is generally used to designate a plurality of plates assembled one upon another, and pack designates said pile doubled or folded back upon itself.

Ingots or bloomsare first reduced to what are commercially designated as sheet and twenty to sixty feet, and are subsequently cut tin-plate bars, which are usually eight inches wide by from onequarter to fiveeighths of an inch in thickness, depending upon the gage and length of the sheets to be produced therefrom. (Sheets being the generic term and black plate a commercial designation, I shall hereinafter refer to the manufactured material as sheets) The bars employed to produce the sheets are rolled in quite longlengths, ranging from into sections approximately equal in length to the width of the sheets to be produced there from. These sections are then heated to a good inellow condition and rolled transversely to their length and into plates three to four times longer than they are wide. When these plates have thus been produced, generallyspeaking,two of them are matched t'. 6., one placed upon the other-and in this relation they are heated in a suitable furnace, and when they have acquired the proper degree of heat .they are withdrawn from the furnace and rolled to elongate them to an approximate length of five feet. After being thuselongated they are separated sufficiently to allow air to come in contact with their inneradjacent surfacesforthe purpose of producingaslight oxid coating, which is designed and has the effect of preventing undue adhesion of the plates during subsequent rolling. It is also necessary to free the plates from each other in order that they maybe doubled or folded back upon themselves and which constitutes the next step in the operation. The last end of these two plates is always more or less uneven, and therefore when the plates are doubled the first end is lapped to just cover a line which when severed upon will cut off the uneven portions, and the pack thus folded is placed under the doubling-machine and the curled end squeezed down into a Hat fold, after which the pack is turned and the uneven end sheared offinthe same machine. The amount of scrap resulting from this shearing operation is always considerable. The plates approximate forty-thousandths of an inch in thickness, and the quantity of scrap varies with the varying shape of the rolls. For instance, in Warming up the mills when the rolls are hollowt'. e., having, concave faces-the sides of the packs are necessarily elongated to a greater extent than the middle portion and produce what are called fishtail ends, meaning that the tail end of the pack has assumed a fish-tail shape, and con-,

sequently in squaring this end wasteful scrap is made. On the other hand, as the rolls become expanded by beat this fish-tail shape is" less pronounced, but usually exists to a greater or less extent, as a pack is flatter and has less of whatis termed the canoe shape when the tail end is concaved in shape rather than convex. The convexed ends indicate that the rolls are too full in their middle portion and cause the dishing or canoeshape pack, which is always to be avoided. From each and every pack this scrap end-must be sheared, it matters not what its shape may be. After the described operation of doubling and shearing, the pack, which is then four-ply, is returned to the furnace to be reheated, when it is again rolled and doubled to form an eight-ply pack, which is sheared in the same manner as already described and in addition the curled end of the pack is cut off in order that the ends of the several plates may be free to adjust themselves in their individual elongation during the next and final rolling,which is done after they have been again returned to the furnace and reheated. After the pack has been thus rolled to afinish and has become cold itis trimmed and sheared into sections of predetermined size, and the sheets constituting such sect'. e., rolled into plates; second, these plates are matched, heated, and rolled into thinner and'longer plates, doubled, and sheared to form a four-ply pack; third, this pack is heated, rolled, doubled, and sheared to constitute an eight-ply pack, and, fourth, this eight-ply pack is heated and rolled to a finish.

Thus, as will be seen, the metal is four times heated and four times rolled and the packs are twice doubled and twice have the scrap sheared from one end.

Y My invention has for its object the reduction of time, labor, fuel, and scrap incident to the hereinbefore-described and ordinary process and incidentally to utilize unskilled or cheaper labor to a greater extent than is now necessary; and with these ends in view my invention consists in the employment of initial bars which are a multiple in weight per lineal foot and preferably a multiple in width of those before described and usually employed in the manfacture of sheets and black plate.

In practicing mynovel invention herein described, the dimensions and weight of the sheets being given, I follow the old estab-- lished rules of determining the necessary weight per lineal foot of the bar required to produce such sheets, which in comparison with the bar of my'improved process may be termed a single bar, which constitutes my multiplicand, and with this as a base I arrive at the multiple weight of bar required by multiplying the multiplicand by any specified number.

As earlier stated in this specification, the sheet and tin-plate bars of commerce are usually eight inches wide by from one-quarter to five-eighths of an inch in thickness. I desire to explain that in general practice it is the thickness and not the width of the bars which is varied to produce sheets of different length and thickness. To illustrate, if a pack of black plate be required from two bars eight inches wide which will shear into sixteen plates twenty inches by twenty-eight inches by thirty gage the bars would be rolled eight inches wide by .366 inch thick and cut into lengths of twenty and one-quarter inches weighing sixteen pounds and three ounces weight may be used.

each. If the same size plates twenty-eightgage be desired, the bars would be rolled thicker, contra for thirty-two-gage plates thinner bars would be rolled, but all eight inches wide. The weight of these initial bars was established many years ago with the introd notion of rolling sheets and black plate in packs, and as the sheet and black-plate mills of to-day are substantially identical with those of early days there has been no change in the average weight of bars, and with the methods now as then practiced heavier bars are no more desired than they were at the earlier period of the art; but with the application of the tandem mill to this branch of the art, as described in my application, Serial No.

138,169, filed January 7, 1903, heavier bars not only become desirable but necessary as an adjunct in the economy of producing sheets and black plate. the bars pass automatically from one pair of rolls to and between each succeeding pair, each pair of rolls making its proportion of reduction, so that bars of the commercial standard thickness and any convenient It will be obvious that by the employment of a tandem mill and the use of bars of the same thickness and from two to four times the weight per lineal foot of the standard bars there will be rolled from two to four times the quantity of plates in a given time than could be produced from bars of one-half or one-fourth the weight. The width and thickness of the bars have in different countries and by different makers varied to conform to individual views and the type of rolling-mill incident to different periods; butwhatever the width and thickness of the bars their weight per lineal foot is established' by the length and thickness of the sheets in pile' or pack to be produced from such bars. For example, sheets in pack of a given length and thickness require bars of certain weight per lineal foot. If packs finished in eights be required, two of these bars will be reduced and worked together in a single pack, being twice don-bled. If packs of sixes'or twelves be desired, three of these bars will be worked together in a single pack, being once doubled for sixes and twice doubled for twelves; but in all cases the weight per lineal foot of bar is established by the length and thickness of the sheets into which it is to be converted. As before stated, the present practice is to rough i. 6., draw out two eight-inch bars into plates about thirty inches long by'rolling them transversely to their length, placing one of these plates upon the other, reheat and roll them in this position into still longer and thinner plates, after which they are opened, doubled into four-ply packs, and the scrap end sheared 01f. It is the waste in scrap made at this shearing that I save by the employment of. bars of preferably the standard thickness and from twice to four times their weight. There is still a greater and In the tandem mill- ICC very important advantage in the use of bars in weight per lineal foot a multiple of those commonly employed, which resides in the fact that a plate rolled from one bar is uniform in its chemical composition, physical structure, and the degrees of'heat absorbed, and as this one bar constitutes a pile or pack all of the sheets in such pile or pack-will naturally draw out uniformly in length and reduce equallyin thickness, which signifies sheets of accurate gage and weight and a decreased quantity of scrap at the final shearing. Obviously the two or three distinct bars which in the present practice constitute a pile or pack may be derived each 'from separate and distinct ingots made at diiferent times, each being difierent from the other in its chemical composition and physical structure, each invaribly varying in degrees of heat when rolled. These constant varying conditions must of necessity beget results commensurately unreliable with their paternal origin.

In roughing the sheet or tin-plate bars of commerce into plates which are matched into pairs and subsequently rolled out together into longer and thinner plates and doubled into four-ply packs the shorter pair of plates as roughed and matched have uneven ends, which are sheared off as scrap after these plates have been drawn out and doubled into said four-ply packs. It mat ters not how wide or narrow the initial bars may be, every bar has but two edges, two ends, and two sides, and by availing myself of this natural law I am able to reduce the end scrap incident to the manufacture of sheets fully one-half, and to accomplish this .desirable economy I employ initial bars of preferably corresponding thickness to the bars of commerce, but from two to four times their weight, whichI rough or roll out into long plates which are the equivalent of plates roughed or rolled from the ordinary bars to be matched into pairs for subsequent red action. It will be noted that the corresponding long and short plates, which are of the same thickness; have each two uneven ends which will produce scrap. Hence in the plates rolled from bars of four times the weight of the ordinary barsl would waste but twenty-five per cent. of the end scrap made from the plates reduced from said or-- dinary bars and but fifty per cent. of said scrap if I employed bars of double the weight of the ordinary bars. These longer plates may be sheared transversely into sections preferably corresponding in length to the plates rolled from the ordinary standard bars and matched into pairs which are rolled and doubed into four-ply packs in the ordinary way; but I desire to call particular attention to the fact that these matched plates sheared from the long it plates have clean-cut square edges and the matched pairs are of equal length, so that there are no overhanging ends to produce waste, as is the case when two plates rolled from two ordinary bars are equal to that of the ordinary bars of commeme 1 largely decrease the percentage of waste in scrap.

In addition to the decreased waste in scrap occasioned by the employment of wider and heavier initial bars and the increased tonnage that can be roughed or drawn out into plates in a tandem will there is still a third advantags in the use of such bars,which is the greater accuracy and facility with which they can be guided to and between each succeeding pair of rolls in a tandem train. It will be remembered that sheet and tin-plate bars are rolled transversely to their length, and as the bars are usually but eight inches wide in the direction they are rolled and of lengths averaging about two feet it will be seen that the problem of automatically guiding them edgewise and squarely to and between the succeeding pairs of rolls of a tandem train is not an easy one to solve. ter the rolls squarely, they will be rolled in a diagonal shape, which would ruin them for further treatment; but by increasing the Width of the bars from two to four times they become nearer rectangular in shape, and consequently easier to automatically guide. If for any reason preferred these longer plates rolled from said heavier bars may be doubled into packs instead of shearing them into sections to be subsequently made into piles or packs, however, the objectionable feature to doubling is the scrap which results from the necessity of shearing off thecurled end when doubled into four-ply packs.

Whilein this specification I refer to standard sheet and tin-plate bars and sheet and tin-plate bars of commerce, I do not confine myself to such bars or to bars of anyfixed width or weight per lineal foot to represent my multiplicand, as from the foregoing description it will be seen that this may be varied to conform to varying conditions and practice, and in citing standard sheet and tin-plate bars and sheet and tin-plate bars of commerce I have done so to briefly designate a material at once recognized by those generally conversant with the art.

It will be understood that the genus of my invention resides in the employment of a bar to be reduced into sheets which is a multiple in weight per lineal foot of a bar of which two or more are required for a pile or. pack to If the bars do not enproduce such sheets, it matters not whether i the bar in condition to be reduced to a plate was sheared from a longer bar which was precedingly rolled longitudinally with or transversely to the direction said bar is to be subsequently rolled in reducing it to a plate and sheets.

While I prefer to employ a tandem train of rolls in operating my invention, because of foot of a sheet or tin-plate bar of which two or more are required to constitute a pile or pack to produce such sheets, reducing said bar into a plate, making said plate into one or more piles or packs and reducing the piles or packs to produce sheets of the required gage.

In testimony whereof I affix my signature in presence of two witnesses.

THOMAS V. ALLIS. Witnesses:

D. G. STUART, J NO. J. HARROWERJ 

